1. Field of the Invention
The present invention relates to light-receiving devices, optical pickups, and optical disc apparatuses. More particularly, the present invention relates to a current-output-type light-receiving device that enables signal transmission in which an effect of a decrease in output impedance is reduced at high frequency, and impedance matching is taken into account, an optical pickup and an optical disc apparatus both of which use the light-receiving device.
2. Description of the Related Art
A known optical disc apparatus such as a DVD or CD apparatus performs recording and playback operations on optical recording mediums using an optical pickup. The optical pickup is provided with a light-emitting device for emitting optical beams for the recording and playback operations, a driving device for outputting current that enables the light-emitting device to emit light, a signal-detecting light-receiving device for detecting signals, and an optical-beam-monitoring light-receiving device for monitoring the optical beams output from the light-emitting device. The signal-detecting light-receiving device is formed as a photodiode IC (hereinafter referred to as a “PDIC”). A front photodiode or a front photodiode IC formed as an integrated circuit is used as the optical-beam-monitoring light-receiving device.
Such an optical disc apparatus is desired to rapidly record and play back information on and from an optical disc. To this end, the optical disc apparatus is configured to rapidly record and play back information by rotating the optical disc using a rotation driving mechanism. More specifically, for example, the optical disc is configured to rapidly record and play back information on and from the optical disc by increasing a rotational speed for rotating the optical disc to a ×8 or ×16 rotational speed in comparison with a predetermined rotational speed, as well as increasing a maximum operation speed of the light-emitting device, the driving device, and the light-receiving device.
In the optical pickup with which information read out from the optical disc is output from the PDIC as a high-speed signal, and in the optical disc apparatus using the optical pickup, the PDIC is connected to a signal processing system including a signal demodulator and an error correction circuit by a relatively long signal line, whereby a signal waveform degrades when a signal passes through the signal line.
As means for preventing such degradation of signal waveforms, an optical pickup and an optical disc apparatus that prevent ringing in a high-speed pulse signal output from the PDIC exist (see, for example, Japanese Unexamined Patent Application Publication No. 2003-132548).
On the other hand, a high-performance PDIC that applies a CMOS process has also been considered instead of the known widely used PDIC that applies a Bipolar process.